The ambiance and sense of space in your apartment affect how you and others feel about it. Therefore, three things that make a huge difference in your apartment are lighting and wall treatments, which influence the vibe your pad gives off, and the spaciousness of it, either in reality or by illusion.
Many people prefer a lot of light in their living areas. If your apartment is in a shady area, give it light by using table lamps and floor lamps. Put bulbs in the range of 5000K to 6500K in them to simulate daylight. You can also get more light by placing a mirror opposite a window.
If your apartment's in an area where there is plenty of natural light, carefully handle your window treatments to take full advantage of the situation. When your curtains cover merely the frame and not the window, more light can enter. An added bonus is that your windows will look wider and, thus, your living spaces will appear larger.
As for the walls, one way to add snap to them is to apply patterned wallpaper. Property managers may not object when you tell them that the wallpaper you’ll use does not have adhesive on it. Instead, you'll use liquid starch to bond it to the wall, and it'll be easy to remove your modern decorating touch later.
Of course, if allowed, you can paint your walls in colors that are bolder than white or beige. Consider painting the lower two-thirds of the wall a different color from the top. This adds not only more interest, but it also gives the illusion of a taller ceiling.
Other ways of making your apartment seem larger include getting rid of clutter and finding pieces of furniture that offer storage. Select a sofa with legs that are exposed rather than one with covered legs. Move furniture a few inches away from the wall. By concentrating on lighting, walls and how spacious your living areas appear to be, you can make a huge difference in your apartment.